Rock-drill.



No. 66|,927; I Patented Nov. 13, I900.

a. L. AMBROSE.

ROCK DRILL.

(Application filed Dec. 11, 1899.) (No Model.) 7 2 Sheets-Sheet l.

WITNESSES:

A] ATTORNEY No. 66i,927.- Patented-Nov. |3, I900.

' B. L. AMBROSE.

ROCK DRILL.

(App lication filed. Dec. 11, 1899.

(No Model.) 2 Sheets- 8mm 2.

WITNESSES: INVENTOR I WMW 4 ATTORNEY Utrrrnn Starts Parana retest ROBERTL. AMBROSE, OF NORTH TARRYTOW'N, NEW YORK, ASSIGNOR TO THE BAND DRILLCOMPANY, OF NEW' YORK, N. Y.

ROCK-DRILL.

SPECIFICATION forming part of Letters latent No. 661,927, dated November13, 1900.

Application filed December 11, 1899. Serial No. 739,878. (No model.)

To all whom it may concern.-

Be it known that 1, ROBERT L. AMBRosE,

a citizen of the United States of America, and

a resident of North Tarrytown, county of \Vestchester, and State of NewYork, have invented certain new and useful Improvements in Rock-Drills,of which the following is a specification,reference being had to theaccompanying drawingsjorming a part thereof.

My invention relates to rock-drills, and particularly to ratchetmechanism therefor.

In a rock-drill in order to obtain the desired results in drilling it isnecessary to intermittently rotate the drill-bar, and the mostsuccessfulway of accomplishingthis has been found to be by mounting aratchet-wheel to rotate with a rotating bar which is spirally groovedand splined to a fixed nut secured to the piston which carries thedrill-bar and by mounting one or more pawls in the drill cylinderhead orsome part stationary therewith.

The piston in movinglongitudinally in one direction is compelled topartially rotate by reason of the ratchet-wheel upon the rotating barbeing locked by the pawl or pawls from itself rotatingin such directionand of the spiral spline connection between the piston and the rotatingbar. In movinglongitudinally in the opposite direction the piston,through the 0 said spiral spline connection with the rotating bar and byreason of the fact that the friction between it and the cylinder isgreater than the friction in the ratchet mechanism, rotates the saidratchet-wheel, causing it to 5 advance one or more teeth under the saidpawl or pawls, according to the pitch of the spiral splines. All this isold in the art and too well known to require detailed description orillustration, except as to such parts as are changed or differentlyconstructed according to my invention.

The objection to the above mechanism as ordinarily constructed lies inthe weakness of the teeth of the ratchet-wheel, and partic- 5 ularly inthe liability of breakage of the pawl or pawls.

It is desirable to rotate the drill-bar but slightly at each stroke, andto so do necessarily limits the size of the teeth upon the ratchetwheel.It is essential, therefore, to

so construct them as to give them thegreatest strength and the leastliability to break. To accomplish this,acute angles m ust be avoided,and in my special construction, to be hereinafter fully described, Ihave so constructed and arranged the said teeth. The most seriousproblem, however, is the construction and arrangement of the pawl orpawls. In

' order to obtain sufficient strength, it has been common hitherto toemploy a hinged pawl or pawls. The objections to the use of such pawlsare numerous. First, the said pawls occupy so much space thatpractically it is impossible to use more than two of them,while it isextremely desirable to use three in order that the load may be evenlydistributed;

secondly, it is difficult to arrange a suitable return-spring for thepawls and one which will not get out of order or break owing to thecurvilinearmovement of the said pawls,

and, thirdly, the pawls have to be arranged in suitable chambers androom left for them to play therein, which causes a space to be left inwhich the air from within the cylinder can pass and into which it willpass at such times as it is desired to lock the air in the cylinder inorder to cushion the piston upon its return stroke.

A pawl or pawls having a rectilinear movement toward and away from theface of the ratchet-wheel and whose axis of movement is radial mightobviate the above three mentioned difficulties. Such pawl, however,provided with an acute-angled face would be very liable to fracture.Pawls used in this connection, by reason of the extreme conditions towhich they are subjected, have necessarily to be hardened or tempered.In such hardening or tempering, as is well known, the less acute theangles of the parts the less liability to internal strain due to theuneven chilling thereof. Further, the less acute the angles the moreevenly disposed the metal, and hence the stronger the part.

I have then, according to my invention, provided the rock-drill with aplurality of springactuated pawls mounted in the drill-cylinder headorin some part secured against rotation with the cylinder-head andarranged that the same shall have a rectilinear movement toward and awayfrom the face of the ratchetwheel, which movement shall be more nearlyradial than tangential, whereby that face of a tooth which is morenearly tangential shall be constituted the lifting-face and that face ofthe tooth which is more nearly radial shall be constituted thelocking-face, the axis of the said movement of the pawl being in a linewhich is eccentric of the axis of the ratchet wheel. The efiect of theabove is to enable me to use as a pawl a block rectangular incrosssection and to construct the ratchet-wheel with teeth ofgreatly-increased strength.

I further arrange the springs, which tend to force the pawls inwardly,in suitable cups, such cups so arranged that they will prevent theescape of the springs from the interior of the cylinder-head should thepawl against which it is hearing be removed for any purpose whatsoever;and my invention further consists in certain details of construction andcombination of parts to be hereinafter more fully described.

I will now proceed to describe my invention with reference to theaccompanying drawings and will then point out the novel features in theclaims.

Figure l is a face view, partly in section, of a ratchet mechanismembodying my invention. Fig. 2 is a transverse section of the same, theplane of section being taken upon the line 2 2 of Fig. 1. Fig. 3 is adiagrammatic view illustrating the principles involved.

Similar reference characters designate corresponding parts throughoutthe several views.

Reference character a designates the upper cylinder-head of a rock-drillas a whole. It comprises three parts-the cylinder head proper, b, theratchet boX or casing c, and the ratchet-box cap or cover (Z. Thesethree parts are usually bolted together and secured to the upper end ofthe cylinder of the rock-drill by bolts passing through apertures inlugs, with which the several parts are provided. The three parts arealso provided with lugs e, the apertures of which coincide, as shown,and which are together arranged to receive thefeed-nutforengagingthefeed-screw. Neither feed-nut nor feed-screw isshown, they being well known and forming no part of this invention.Reference character f designates the rotating bar, a portion only ofwhich is here shown and which is spirally splined to and operates inconjunction with the reciprocating piston, all in a manner well known,to intermittently rotate the drill-bar.

g designates a ratchet-wheel which is secured to rotate with therotating bar. The said ratchet-wheel is mounted within the said saidratchet-box c and between the head I] and the cover d. The ratchetwheelsubstantially fits the said ratchet-box diametrically, so that the faceof the teeth will rotate in close proximity to the inner face of theratchet-box c.

72 designates pawls, of which I may use one or more, but of which Ipreferablyuse three, as shown. The pawls consist each of a rectangularblock having that face which is against the teeth of the ratchet-wheelperpendicular to the line of movement of said pawl. By reason of thissquared end the pawls present a surface the entire thickness of theblock, which must be sheared off before the pawl will give way. A pawlwhich has its end cut at an acute angle may easily be broken across thecorner at a point which is narrower than the full width of the block,and this is all the more likely on account of the fact that this part islikely to have been made the hardest and hence the most brittle in thetempering process to which said pawls are subjected. The use of asquare-ended pawl in this connection is hencewery desirable. I will nowproceed to describe myimproved construction and arrangement of partswhich will permit of such use.

The before-mentioned pawls are mounted in the cylinder-head a and areguided endwise between the two heads I) and (1. Sidewise they are guidedin suitable ways out in the inner wall of the ratchet-boXca-nd whichextend the entire width thereof. These ways are so cut that the saidpawl-block shall have its squared end fiat against that face of a toothof the ratchet-wheel which is the more nearly tangential at the momentthat that face of the adjacent tooth is against the side of the pawl; Asa result it will be seen that the axis of the line of movement will becccentric of the axis of the ratchet-wheel. In Fig. 3 I have shown adiagram illustrative of this arrangement. 15 is a circle representing,for instance, the peripheral circle of the ratchet-wheel. u is a lineradial of the said circle and intersecting the center of the circle att, which may be considered the axis of the ratchet-wheel. h is one ofthe beforementioned pawls, and w designates its axis of movement. Itwill be seen that by placing that end of the pawl which is perpendicularto its line of movement flat against that face of a tooth which is themore nearly tangential at the moment that the working or side face ofthe pawl is against that face of a tooth which is the more nearlyradialthe said axis of movement to will be in a line which is eccentric of theaxis o of the ratchet-wheel. designates that face which is the morenearly tangential and which is the lifting-face of the tooth, and ydesignates that face which is the more nearly radial and which is theworking face of the tooth.

I preferably so construct the teeth of the ratchet-wheel and so mountthe pawl that the working face of the pawl is and has a movement in aline which would pass upon that side of the axis of the ratchet-wheelwhich is in a direction opposite to the direction of the rotation of theratchet-wheel. In the diagram, 2 designates the line of the working faceof the pawl 7b, and said line, as will be seen, upon being producedpasses the axis of the ratchet-wheel upon that side thereof I'IO suchwidth.

which is opposite to the direction of rotation of the ratchet-wheel.Such direction of rotation is indicated by an arrow in Fig. 3.

It will be seen that not only does the foregoing arrangement permit apawl to be made which is very much stronger, but also permits the makingof very much stronger teeth upon the ratchet-wheel, the said teeth beingundercut in no part whatever. The pawls are pressed inwardly against theface of the ratchet-wheel by means of helical springs 2', onefor eachpawl being preferably provided, though of course there may be more, ifdesired. These springs are mounted in cylindrical housings in theratchet-box c. The diameter of these housings is greater than the widthof the pawlways, and the diameter of the springs is preferably alsogreater than Hence if the pawl be removed through the interior of theratchet-box they will not he accidentally displaced through thepawlways. Furthermore, I have found that if the springs be of too smalladiameter they are liable to become gumrned up by oil and dirt whichworks into the housing and in time tends to set. The use of a largerpawl overcomes this difficulty to a considerable extent.

A suitable cap j is provided for each housing and is preferably tappedinto the ratchetbox from the outside and allowed tq fetch up against ashoulder. This cap closes the outer end of the spring-housing and formsa backstop for the spring contained therein. A square socket is shown,or equivalent means may be employed, by which the said cap may bescrewed into place.

75 designates a follower arranged 'to slide freely in the spring-housingand is located between the inner end of the spring and the outer end ofthe pawl. It is here shown as cup-shaped and receives one end of thespring t', transferring the pressure thereof to the said pawl. Thediameter of the follower is greater than the thickness of the pawl andhence of the width of the pawlways. Thus the said follower will retainthe spring from displacement regardless of the diameter of the spring.If, therefore,'the follower be employed, it is not entirely essential,though it is preferable, that the diameter of the spring itself begreater than the width of the pawlways. The pawls are of course bothremoved from and inserted through the interior of the ratchetbox abefore the insertion or after the removal of the ratchet-wheel.

I have shown and preferably provide three pawls equidistantly around theratchet-wheel and so arrange them that they are all in engagement withthe teeth of the ratchet-wheel at the same time. Such arrangementlargely augments the strength of the parts and saves side thrust. Theseparts require to be of great strength for practical use. The drill willoften strike on a portion of rock which is oblique or which is hard onone side and soft on the other. The consequence of this is that theratchet-teeth and the pawls are called upon to stand an enormous shock,and they must be'so constructed as to stand this shock. For this theyrequire a maximum of strength, and I have shown and described a ratchetmechanism which fulfils these requirements to the highest degree andwhich at the same time combines simplicity and cheapness ofconstruction.

For the purposes of this specification and claims I have described thepawls and ratchet as being mounted in the cylinder-head. Theratchet-wheel I have described as rotating freely therein except for itsengagement with the pawls engaging therewith and the pawls mountedtherein and having a movement toward and away from the ratchet-wheel.

For the same purposes I have shown and described the three parts I), c,and cl as constituting an upper cylinder-head as a whole. It may be ofone piece; bu t for purposes of manufacture it is preferable to make itas shown. The ratchet-box being a separate piece, the pawlways mayeasily be milled right across, which is a very inexpensive undertakingcompared with the cutting of such ways were this not a separate part.

It is of course understood that the pawls may be mounted on or in anypart which is secured with the cylinder-head against rotationirrespective of whether it is a part of or secured directly to thecylinder-head or not and that the ratchet-Wheel may likewise be suitablyarranged where desired, provided it is secured to rotate with therotating bar.

What I claim is 1. In a rock-drill, the combination with a rotating barand a ratchet-wheel secured to rotate therewith, of a spring-actuatedpawl mounted in the drill cylinder-head and having a rectilinearmovement therein toward and away from the face of the ratchet-Wheel,that end of the pawl engaging the teeth of the ratchet-wheel beingperpendicular to the line of movement of the said pawl, and arranged toengage with that face of a tooth of the ratchet-wheel, which is the morenearly tangential, said face constituting the liftingface of the saidtooth.

2. In a rock-drill, the combination with a rotating bar and aratchet-wheel secured to rotate therewith, of a spring-actuated pawlmounted in the drill cylinder-head and having a rectilinear movementtherein toward and away from the face of the ratchet-wheel,

the axis of said movement being in a line which is eccentric of the axisof the ratchetwheel, the inner end face of said pawl being at rightangles to said line of movement and arranged to engage with that face ofa tooth of the ratchet-wheel which is the more nearly tangential, saidface constituting the liftingface of said tooth.

3. In a rock-drill the combination with a rotating bar and aratchet-wheel secured to rotate therewith, of a springactuated'pawlmounted in the drill cylinder-head and having a rectilinear movementtherein toward and away from the face of the ratchet-wheel, the workingface of the pawl having a movement in a line which passes the axis ofthe ratchetwheel upon that side thereof which is in a direction oppositeto'the direction of rotation of the ratchet-wheel.

4:. In a l ock drill, the combination with a rotating bar and aratchet-wheel secured to rotate therewith, of a pawl mounted in ways inthe drill cylinder-head and having a rectilinear movement therein towardand away from the face of the ratchet-wheel, and a helical springmounted in the drill cylinder-head and adapted to press the said pawlinwardly against the face of the ratchet-wheel, and means to limit theinward movement of the spring whereby the said spring will be retainedfrom accidental displacement through the pawlways, after the said pawlhas been removed.

5. In a rock-drill, the combination with a rotating bar and aratchet-wheel secured to rotate therewith, of a pawl mounted in ways inthe drill cylinder-head and having a rectilinear movement therein towardand away from the face of the ratchet-wheel, and a helical springmounted in the drill cylinder-head and adapted to press the said pawlinwardly against the face of the ratchet-wheel, the said spring being ofsuch size diametrically as will prevent the same from accidentaldisplacement through the pawlways, after the said pawl has been removed.

6. In a rock-drill, the combination with a rotating bar and aratchet-wheel secured to rotate therewith, of a pawl mounted in thedrill cylinder-head and having a rectilinear movement therein toward andaway from the face of the ratchet-wheel, a helical spring mounted in thedrill cylinder-head and adapted to press the said pawl inwardly againstthe face of the said ratchet-wheel, and means interposed between thesaid pawl and the said spring whereby the spring is retained fromaecidental displacement through the pawlways after the said pawl hasbeen removed.

8. In a rock-drill, the combination with a.

rotating bar and a ratchet-wheel secured to rotate therewith, of a pawlmounted in the drill cylinder-head and having a rectilinear movementtherein toward and away from the face of the ratchet-wheel, a helicalspring mounted in the drill cylinder-head and adapted to press the saidpawl inwardly against the face of the said ratchet-wheel, and acupshaped follower interposed between the inner end of the spring andthe outer face of the pawl, the said cup-shaped follower being ofgreater width than the width of the pawlways.

9. An upper cylinder-head for a rock-drill comprising three pieces: acylinder head proper, a ratchet-box, and a cover therefor; the saidratchet-box having a cylindrical bore therethrough, adapted to receive aratchetwheel, and having a plurality of pawlways, each adapted toreceive a rectangular pawlblock, communicating with the said cylindricalbore and extending the entire width of the ratchetbox, and a pluralityof cylindrical spring-housings, one for each of the said pawlways,thediameter of the said springhousings being greater than the width of thesaid pawlways.

ROBERT L. AMBROSE.

Witnesses:

HUGH V. CONRAD, W. J. BARNUM.

